[R-390] Power supply capacitors

[David Wise]

When I did my LM317-based current regulator (before starting
on the 3DW7), I included a power resistor in series with the
rectifier to reduce the peak current and increase the
conduction angle.  I forget the value.  I recommend you
include this in your experiments.

Dave Wise

> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of kenny
> Sent: Wednesday, June 11, 2008 4:30 AM
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] Power supply capacitors
> 
> That's really interesting what you say Gord about the extra energy 
> showing itself as heat in the regulator. That didn't even 
> occur to me. 
> My particular circuit uses a 2200uF and LM317 (among other things) to 
> produce a stable and regulated 12.6 volts for the filaments 
> of the BFO 
> and PTO tubes and the regulator DOES run hot...even with a good sized 
> heatsink it will heat up the heatsink quite nicely. I had a nagging 
> feeling 2200uF was too big....so I'm going to start playing with it 
> until I feel I have a good balance between acceptable performance and 
> long term reliability.
> 
> Regards, Ken (ZL3AA)